The invention relates to an arrangement of electrically drivable solenoid valves, a central plug and a printed circuit board on a control housing for an automatic shift device of a toothed-wheel variable-speed gearbox.
In a known arrangement of the type referred to above (German Patent Document DE 37 09 505 Al), the printed circuit board is arranged at the front end, lying respectively opposite the control housing, of the solenoid valves so that column-like spacing elements are required to secure the printed circuit board to the control housing. The solenoid valves are clamped into the control housing at their end regions adjacent to said control housing by means of a common securing plate, that is to say separately from the printed circuit board. Furthermore, with the known arrangement it is costly that the socket of the central plug is secured in a housing opening of the control housing itself in a nondisplaceable fashion so that in order to make contact with the printed circuit board a finger-like projection is required which bridges the distance between the control housing and the printed circuit board.
German Patent Document DE-GM 18 35 715 discloses a switchbox for the arrangement of electromagnetic relays for controlling a motor vehicle gearbox. Because of the constant driving vibrations, important considerations with this gearbox were a reliable connection of the relay terminal contacts to the control lines and, because of the restricted space, the most compact possible accommodation of the entire arrangement in the motor vehicle. Furthermore, there was also the following secondary problem with this switchbox. The solder connections of the relay terminal contacts were most at risk from vibrations since the mass oscillations between the heavy relays and the lines could cause resonance phenomena at the attachment points, which phenomena as in the case of clamp connections, had the tendency to detach individual lines. In addition, the production of the solder terminals and their accommodation required sufficient space and additional attachment means for the relays. In the case of relays provided with terminal plugs, the lines were led to plug bases in order to permit the relays to be changed conveniently without, however, the object, of avoiding solder connections because of their sensitivity and in order to save space, on which the production of the switchbox is based having been achieved since in the case of the relays which are provided with terminal plugs the said solder connections would now be located at the base contacts. In order to achieve the described object, in the case of the known switchbox the arrangement is made such that the relays are plugged onto a baseplate in the switcbox in that plug devices which are provided on each relay and are permanently connected to mechanical parts of the relay engage directly in bushing-like recesses of the baseplate, which recesses at the same time form the terminal contacts for a prepared circuit. The plug-in openings which are provided in the baseplate are configured with wire straps which can be expanded in a sprung fashion and into which pins which are attached to the magnetic yokes of the relays engage with locking grooves. The baseplate is provided with a printed circuit whose connection points for the relays or other switching elements are formed by bushings into which contact parts of the relays which are constructed in a plug-like fashion directly engage.
German Patent Document DE 32 36 535 A1 discloses an open-loop or closed-loop control system which contains at least one signal transmitter (control instruction and/or measured value signal transmitter), one electronic evaluation circuit for the signals of the signal transmitter and at least one solenoid valve which is driven by this electronic evaluation circuit and is connected into an hydraulic or pneumatic actuation system, the evaluation circuit being arranged in the vicinity of the valve. In this publication, the following problem is taken as the starting point. For example, in anti-lock brake control systems for vehicles it is known to accommodate the evaluation circuit in the passenger compartment and to connect the sensors assigned to the wheels and the actuation valves for varying the brake pressure to the evaluation circuit by means of cables and one or two plugs. It is also known to arrange the evaluation circuit in the vicinity of the actuation valves. However, it would be necessary to use here the same number of plug-in connections, which are the cause of faults, as previously. These considerations are also intended to apply to other closed-loop or open-loop control devices. In order to avoid these problems, the teaching of the publication is that the evaluation circuit and the electromagnet or electromagnets of the solenoid valves are accommodated in a common housing and connected to one another, that the valve parts of the at least one solenoid valve are accommodated in a separate block, that the common housing is joined to this block, and that the at least one valve can be actuated via at least one tappet which leads out of the common housing and can be displaced by the at least one electromagnet.
In German Patent Document DE 30 41 707 Al, an electromagnet valve for fluids with an armature constructed as a closing element is disclosed, the armature being part of a magnetic circuit and simultaneously fulfilling hydraulic functions. The problem addressed in the publication is related exclusively to the solenoid valve for which reason the solution to the problem is seen in an electromagnetic valve for fluids with an armature constructed as a closing element, in which electromagnet valve on the one hand the armature is part of a magnetic circuit and simultaneously fulfills hydraulic functions and on the other hand the intention is that the improvement should consist in the closing element being constructed at least approximately as a cylindrical element with spherical caps at both ends. In the publication, an arrangement of solenoid valves is shown on a control housing in which, inter alia, switching valves are accommodated which set the working pressure of shift actuators of an automatic shift device of a toothed-wheel variable-speed gearbox in each case as a function of the pressure of an associated solenoid valve. In this known arrangement, the valve axes of the solenoid valves are arranged perpendicularly to a reference plane of the control housing in which support faces which are assigned to the solenoid valves and lie in each case in housing planes parallel to the reference plane are provided on the upper side which lies at the top in the installation position. The solenoid valves are fixed with respect to the control housing in the directions parallel to the reference plane in each case by means of the positively engaging seating of a valve housing base which is coaxial to the valve axis in a corresponding receptacle, having the associated support face, of the control housing and in the direction perpendicular to the reference plane and pointing away from the control housing by means of retainers, the retainers engaging in each case on a corresponding counteracting face of the solenoid valve housing of a solenoid valve. The end side, lying opposite the control housing, of a solenoid valve housing is used as counteracting face, the solenoid valves being clamped in pairs with their counteracting faces by means of a common retainer in each case, the said retainer being anchored on an attachment screw which can be screwed into a threaded hole of the control housing.
In DE German Patent Document 93 07 228 U1, a control system, in particular gearbox control system for a motor vehicle is disclosed, the said control system having a housing which is partially filled with oil and in which electrical, mechanical and/or hydraulic control means are arranged, and having functionally associated control electronics. In this known control system, the space available in the gearbox casing is used because the control electronics are arranged inside the casing. An advantage of this known control system is that the lines to the control means which include the automatic gearbox with its shafts, gearwheels, clutches, brakes, etc., and a functionally associated hydraulic control with oil pump, throttle valves, controllers, sensors and hydraulic valves in order to change the gears, detected by the control electronics, of the gearbox, are very short and lines are dispensed with. Also, only a small number of plug components is required.
German Patent Document DE 28 36 166 B1 discloses a centralized electric system in motor vehicles for receiving line connections, fuses, relays and plugs and/or couplings for the connection of cable harnesses, the said centralized electric system consisting of a plurality of insulating plates which are arranged one on top of the other and bear conductor tracks on both sides, a number of which conductor tracks being through-contacted, depending on the circuit requirements, on one side of an insulating plate with conductor tracks on the other side of the same insulating plate and/or with conductor tracks of one or more further insulating plates, at least one insulating plate having fuse elements, relay holding elements and plug connecting elements. In order to produce a centralized electric system which considerably reduces the outlay in terms of punching tools and avoids through-contacting of the conductor tracks of different printed circuit boards with one another via riveted and/or soldered pins, and excludes internal plug-in connections between conductor tracks and fuse mounts and relay connections, makes the plug-in connection system more variable, improves operation, permits simple, cost-effective assembly and in which circuit changes can be carried out easily and quickly without a large cost outlay, the known centralized electric system is constructed in such a way that the conductor tracks are attached as linear belts, which are insulated at least on one side and whose ends can be constructed as plugs, at a specific lateral distance, which corresponds to that of multi-plug connectors which can be connected thereto, in grooves arranged in parallel on both side faces of the insulating plates, and that second conductor tracks which are also insulated at least on one side are secured, perpendicular to the first conductor tracks and lying directly above them, at the same lateral distance as the first belts in grooves, arranged in parallel, in the insulating plates, the insulated side faces of the first and second conductor tracks facing one another and these intersecting conductor tracks of one side of an insulating plate being connected both to one another and to conductor tracks of the other side of the insulating plate in accordance with the circuit requirements by means of spot welding to one another.
An object on which the invention is based consists essentially in simplifying the securing elements for the parts arranged on the outside of the control housing and the assembly of such an arrangement in an arrangement of the type referred to above.
The disclosed object is achieved according to preferred embodiments of the invention by utilizing the printed circuit board housing for multiple functions including securing a socket for a central plug and anchoring retainers for the solenoid valves.
In the arrangement according to the invention, the printed circuit board,which advantageously rests directly on the top of the control housing, has further functions in addition to receiving line connections between the central plug and the electrically drivable solenoid valves. Thus, the printed circuit board additionally serves to secure the socket for the central plug and to anchor the retainers for the solenoid valves. The printed circuit board thus forms a premountable electric kit whose electrical functions can be tested before installation on the control housing, for example with the aid of a diagnostic device. In the arrangement according to the invention, the securing both of the printed circuit board and of the solenoid valves to the control housing is simplified.
In the arrangement according to the invention, it is made easier to assemble and replace the solenoid valves by virtue of detachable contacts between the printed circuit board and the respective solenoid valve.
In the arrangement according to the invention, larger cross-sections for the conductor tracks and thus stronger currents are made possible by using punched sheet-metal parts.
In the arrangement of the invention, savings in material are made on the securing of the solenoid valves by individual retainers, and not a sheet-metal plate which is common to all the solenoid valves, being used to secure the said solenoid valves.
In the arrangement according to the invention, the conductor tracks are arranged countersunk with respect to the adjoining surface of the printed circuit board so that shortcircuits as a result of extraneous particles are avoided and the creepage current paths are increased.
In the arrangement according to the invention, the printed circuit board is additionally used to receive a temperature sensor, connected to the central plug by means of conductor tracks, for the temperature of the working oil so that a special housing with a special line routing for the temperature sensor is avoided.
In the arrangement according to the invention, the printed circuit board is additionally used to receive a start-inhibit switch which is connected to the central plug by means of conductor tracks and only permits the drive engine to be started when the selector lever is in the positions N (Neutral) and P (Park), as a result of which a special switch housing and a special line routing for this switch are avoided.
In the arrangement according to the invention, the printed circuit board is additionally used for the premountable securing element, which is movable to a limited degree, for a housing which receives at least one speed-of-revolution sensor, the speed-of-revolution sensor being connected to the central plug by means of conductor tracks. In order to obtain its limited movability, this housing can be constructionally connected to the printed circuit board exclusively by means of the conductor tracks. In the arrangement according to the invention, the socket of the central plug is mounted so as to be movable to a limited degree with respect to its securing element which is provided on the printed circuit board, so that the central plug can be aligned with respect to a significant housing hole of a gearbox casing of the toothed-wheel variable-speed gearbox, which casing receives the control housing on its underside.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.